Acrylates have been employed as binder ingredients for solid propellant compositions. Acrylates which have been copolymerized with acrylic acid have also been employed as a copolymerized binder system. Taken an additional step further, acrylates have been employed as a member of a terpolymer system for a propellant binder system. As an example, a terpolymer comprised of butadiene, carboranyl methacrylate (CMA), and acrylic acid was disclosed and claimed in U.S. Pat. No. 3,914,206 by Chester W. Huskins and assigned to The United States of America as represented by the Secretary of the Army. The burning rate of the propellant containing CMA of about 75% of the terpolymer (or of about 15% CMA of the propellant composition based on 20% use of the terpolymer) resulted in a burning rate of about 3.5 inches per second as compared to a burning rate of about 0.25 inches per second for 0% CMA, both measured at 1000 psia. Thus, the terpolymer served as a combination binder and burning rate catalyst for the solid propellant compositions to achieve improved burning rate.
Thus, the polymeric systems employing an acrylate have proven to be useful as a binder for solid propellants. They are compatible with a wide variety of propellant ingredients such as the carboranes, difluoroamio compounds, oxidizers, and additives. These propellents employing acrylates are easily cured with epoxy type curing agents. The mechanical properties have been of acceptable values for propellants subjected to average accelerations. The burning rates have also been of acceptable values in the range of about 14 inches per second at 1000 psia and in the range of about 22 inches per second at 2000 psia.
Because of the acceptability of acrylates for their intended uses, improvements in the specific impulse due to the use of an energetic acrylate in the binder system would offer an additional advantage.
Therefore, an object of this invention is to provide an energetic acrylate for use in a solid propellant composition to yield a higher specific impulse and a higher burning rate for the propellant composition.
Another object of this invention is to provide a high energy, high performance, ultrahigh-burning rate composite propellant which employs an energetic acrylate copolymerized with acrylic acid as the binder system.